Condenser and method of making same



Feb; 11, 1930. w. c. GRUNOW 1,746,469

CONDENSER AND METHOD OF MAKING SAME Originl Filed Feb. 18, 1927 2Shets-Sheet l Feb. 11, 1930. w. c. GRUNOW CONDENSER AND METHOD OF MAKINGslum Original Filed Feb 1a, 927 2 Sheets-Sheet 2 Width/7L G. GTTLLTLO wgig Patented Feb. 11, 1930 UNITED STATES. PATENT OFFICE WILLIAM: G.GRUNOW, OF CHICAGO, ILLINOIS, A SSIGNOR; TO GRIGSBY-GRUNOW COHL PANY, OFCHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS CONDENSER AND METHOD OFMAKING SAME Application filed February 18, 1927, Serial No. 169,417.Renewed December 30, 1929.

My invention relates in general to electrical condensers, and animproved method of making the same.

It relates more-in particular to the production of paper-foil condensersadapted to be potted singly or in multiple form to produce a finishedcondenser of requisite capacity.

Among the principal objects of the present invention, is to provide acondenser with improved electrical characteristics.

Another object is to produce a condenser having a. longer life.

Another object is to produce a condenser whose electricalcharacteristics will be constant.

Another object is to provide an improved method of manufacturingcondensers.

Another object is to provide a method whereby condensers of a superiortype may be constructed more economically than heretoiore.

The principal novel steps of the method are indicated in theaccompanying drawings, wherein- Fig. 1 shows the condenser as wound;

Fig. 2 illustrates the manner in which it is flattened;

Fig. 3 shows its appearance after it has been impregnated and before itis coated;

Fig. 4 represents its appearance after the coating step;

Fig. 5 is a vertical sectional view showing the way the condensers maybe placed in the pot preparatory to being sealed therein, and

Fig. 6 is a, similar view illustrating the manner in which thecondensers are sealed in the pots.

In general my condenser comprises a paperi'oil condenser body, entirelyenclosed in a continuous imperforate shell of thoroughly non-hygroscopicmaterial, preferably a material such as chlorinated naphthalene. Themethod comprises winding the paper-foil body in a suitable manner,baking it to remove all vestiges of moisture therefrom, thoroughlyimpregnating the condenser in liquefied chlorinated naphthalene or thelike, applying pressure to the flat sides of the condenser until thechlorinated naphthalene has solidified, and finally forming animperiorate shell of chlorinated naphthalene about the condenser body ina suitable manner as by dipping or the like.

Although the invention is directed more in particular to the productionof the sealed casing or shell about the condenser body, still I obtainthe best results by controlling the preliminary steps of the process incertain respects. The process has been developed of course not only toproduce the best condensers of the type which can be made, but also toproduce them economically.

In winding the paper and foil to produce the condenser body, I employ around mandrel 10. The foil 11 and paper 12 are partly wound, the usualterminals 13 and l i applied in contact with the foil, and the windingresumed until the proper number of turns have been taken. The outersection of paper is then secured in place by the use of any suitablesubstance such as a gum-mastic or gum arabic adhesive.

The mandrel is then removed from the condenser, and the paper and foilbody collapsed to form a body of oval cross-section as shown in Fig. 2.These bodies are then assembled in a suitable tray, and baked under avacuum to remove all vestiges of moisture therefrom. When they arethoroughly mois-' ture free, they are subjected to the impregnating stepof the process.

The impregnating material whichI employ is preferably chlorinatednaphthalene. In actual practice I have used the chlorinated naphthalenewhich is sold to the trade under the name of Halowax. I may employhowever, other materials which are substantially as non-hygroscopic aschlorinated naphthalene. Indeed by observing certain details of myprocess, much better results can be ob tained with such impregnatingmaterials as paraffin or ozocerite than have been obtained y the use ofthese materials in the past. The impregnating material is heated toreduce the same to liquid form, and the moisture free condensers areimmersed therein. A vacuum of at least twenty-eight inches is maintainedabove the impregnating liquid until substantially all of the air isremoved from the condensers, and the impregnating liquid has replacedthe same. When this condition exists a pressure greater than at-.mospheric pressure preferably about one against their flat sides, andretained until the impregnating liquid has cooled sufficiently to becomesolid and-the condenser is self-sustaining. This time varies, dependingon weather condition, but normally is approximately two hours.

3 When the condensers have cooled they are removedfrom the trays andwill be found to have the appearance indicated by Fig. 3.

While they r are thoroughly impregnated there are still exposed edges 15and holes which permit moisture to enter, particularly if the condensersare allowed to stand for any length of time to overcome this difliculty,the condensers are then sealed before they have absorbed enough moisturefrom the atmosphere to deleteriously affect their insulation resistance.I aim to perform the sealing operation as soon afterremoval from thetrays as possible. During humid seasons I-take particular precautions toseal the condensers without delay, and they are accordingly dippedimmediately when they are removed from the trays. When the condensersare dipped they acquire a coating 16 on the outside thereof, thiscoating being entirely imperforate so that it acts as an absolute sealof the openings 15. This coating 16 is found to have filled up aroundthe terminals to form enlargements16 which have theefie'ctof thoroughlysealing the condensers at the place terminals emerge from between thepaper and foil.

" y In the dipping operation I use aliquefied sealingmaterial,preferablythe sameas employed in the impregnating operation. Mybest-results have been obtained with chlo-r :rinated naphthalene. Afterbeing dipped,

' the condensers are immediately removed and the'liquid which adheresto'the surface there ing ' of quickly solidifies, and this results'infor'mthe shell-like casing around the outside of the condenser.

After the-dipping the operator enamines l the condenser, particularlythe ends thereof, and if any unevenness or irregularity shows, they areagain dipped to avoid 'the possibility of small opening:\ remaininginthe shell-like casing. When s dipping opera tioirhas -beencompleted, ashell of chlorinated naphthalene has been fofmed completely aroundtheconde'nserbody.

condensers.

through. .Even here however,'a perfect seal 1 is obtained because thechlorinated naphthalene grips the base of the terminal firmly enough toprevent all absorption of moisture at this point.

After the unit condensers are produced, I

they are potted in any proper manner either" individually or, as isusually done, in multiples of several condensers therefore resulting ina large condenser of increased capacity.

The method which I have employed in potting the condensers, is topreliminarily make the necessary connections between the terminals ofthe condensers which are to be includedin the pot or casing and thenplace the condensers into a pot oncasing after the bottom thereof hasbeen covered with a sealing compound. After the condensers 'are in thepotor casing, the sealing cdmpound is pourediover the top thereof. Thesealing compound may vary and may include asphalt materials with variouswaxes, or may consist solely of the black wax-like substance which goesunder the name of ordinary black sealing wax. I

The specific step which is entirely new with me in the productionof'condensers asfaras I am aware, is the sealing of the condensers in ashell-like casing of non-hygroscopic material such as chlorinatednaphthalene, immediately after they have been impregnated and theimpregnating material has solidi-- fied. By the use of this practice, myprocess is rendered more economical, and the resulting condenser much suerior to any condensers of this type hereto ore produced.

My process eliminates the second baking step which is usually ap lied tothe condenjections, almost erfect electrical results being obtained.-

I obtain a better condenser by the use of my process because there is noopportunity for-the absorption-of moisture between the impregnating stepand the potting of the one to two days to progress the condensersthroughthis portion o be manufacturing It takes on an average, fromprocess and it is'apparent-that a great deal of moisture can bea sorbedduring this time when the condensers arenot preliminarily sealed. Thistime of from one totwo days or more is required in the ordinary processand moisture therefrom. It has become very apparent to me that with theusual sealing compounds employed in this operation, considerablyinsuflicient protection is afforded the condensers; and that condensersproduced in the old way will invariably cover a period of years or evenmonths sometimes, absorb sufiicient moisture to greatly impair theirperformance.

I believe that some of the advantages possessed by my condenser are dueto the use of chlorinated naphthalene instead of parafiin, which is thematerial most commonly used in the past for impregnating condensers.Paraffin is slightly hygroscopic, but so little so that the moistureabsorbed thereby was not supposed to affect the capacity of thecondenser in any way. I believe however, that the better results which Ihave obtained indicate that this small amount of moisture may have adeleterious efiect upon the life and performance of the condenser.

My improved condenser depends for its value, not only upon the provisionof a sealing thereof before potting and before they have had time toabsorb sufiicient moisture in the subsequent steps of the process todeleteriously affect their insulation resistance, but also upon the useof such a material as chlorinated naphthalene. As far as I am aware, Iam the first one to employ this material in this way.

In the use of my condenser body as suggested previously Imay employ anyof the standard methods heretofore used. It is custernary to potcondensers in proper numbers to secure the capacity desired in aparticular instance and in this potting operation I use the same generalarrangement and the same general process heretofore used.

Reference may be had to Figs. 5 and 6 showing one specific manner inwhich the potting may be performed. A container 17 generally of metal isprovided and a layer 18 of sealing compound is preliminarily placed inthe bottom thereof,'and the condensers in proper number set into the potand on top of the sealing compound 16. The height is arranged so thatthe terminals 13 and 14 project upwardly beyond the container. Sealingcompound 19 of any suitable material, such for example as a mixture ofasphalt and rosin oil, etc.,.is put in around the condensers to entirelyenvelope the same while leaving the terminals projecting freely at thetop. In

connection with the potting operation it is sometimes customary to dipthe condensers into a suitable sealing compound just before they areplaced in the pets for the purpose of insuring the formation of asatisfactory seal without the inclusionof air bubbles or the likeimmediately in contact with the condenser-body. I may employ this stepof the process where it is deemed necessary but I find that I am able toobtain a satisfactory seal in most cases without this preliminarydipping step.

I or purpose 'of illustration, I have described certain details of mycondenser and the method employed in the manufacture thereof, but it isobvious that I do not limit myself to these specific details, theinvention being restricted only by the scope of the appended claims.

What I claim as new and desire to secure by United States Letters Patentis:

1. As a new article of manufacture an electrical condenser body adaptedto be sealed in a container, said body being impregnated and coated withchlorinated naphthalene.

2. As a new article of manufacture an electrical condenser body adaptedto be sealed in a container, said body being impregnated withchlorinated naphthalene, and enclosed in an imperforate shell ofchlorinated naphthalene, the terminals only breaking the continuity ofsaid shell, and the shell firmly gripping the base of said terminals toprovide anabsolute seal at these points.

3, The method of manufacturing an electrical paper-foil condenser bodyadapted to be sealed in a container, which comprises winding saidcondenser body upon a round relatively large diameter mandrel, removingthe mandrel and collapsing the condenser to oval cross-section form,removing the moisture from said condenser body, impregnating thecondenser body with chlorinated naphthalene, and finally forming animperforate shell of chlorinated naphthalene around the moisture freecondenser body.

4.. The method of manufacturing an electrical paper-foil condenser bodyadapted to be sealed in acontainer. which comprises winding the paperand foil in alternate layers upon a round relatively large diametermandrel to produce a condenser body, removing the mandrel and collapsingthe condenser to oval cross-section form, baking said condenser body toremove the moisture therefrom, impregnating said condenser body withheated liquefied chlorinated naphthalene, applying a predeterminedpressure to the i1npregnated condenser body until the chlorinatednaphthalene has solidified and finally forming an imperforate shell ofchlorinated naphthalene around the moisture free impregnated condenserbody.

5. The method of manufacturing an electrical paper-foil condenser whichcomprises winding the condenser body. impregnating such body in heatedliquefied impregnating material, pressing the condenser until the impregnating material has solidified and then forming an imperforate shellof'insulating material about the condenser body immediately and beforethe application of further process steps to the condenser such astesting.

and the like.

6. The method of manufacturing an electrical paper-foil condenser whichcomprises Winding the condenser body, impregnating such body in heatedliquefied impregnating material, pressing the condenser until theimpregnating material has solidified, forming an imperforate shell ofinsulating material about the condenser body, joining the condenserbodies in banks, placing a bank in a pot, and pouring sealing materialaround the condenser bank to complete the potting.

In witness whereof, I hereunto subscribe my name this 15th da ofFebruary, 1927. WILL C. GRUNOW.

